Production method of 6-hydroxy-2-naphthoic acid

The invention discloses a production method of 6-hydroxy-2-naphthoic acid. The production method comprises the following steps: A, salt forming reaction; b, dehydrating and drying: dehydrating and drying the first product; c, carboxylation and dissolution; d, neutralizing and filtering: adding acid into the second product solution, neutralizing until the pH is regulated to 6.6-6.7, filtering, and carrying out oil-water separation on filtrate to obtain a water-phase product and an oil-phase product; e, decolorizing: decolorizing the water-phase product, and then circularly filtering until the filtrate is clear; f, acid precipitation: adding acid into the clarified filtrate to adjust the pH value to 2.0-2.5, and filtering to obtain a filter cake, namely a 2, 6 acid crude product; g, refining and drying: decoloring the 2, 6 acid crude product and removing trace 2, 3 acid to obtain 2, 6 acid with the 2, 6 acid content of 92%-95%, and the 2, 6 acid is 6-hydroxy-2-naphthoic acid. The invention aims to provide a pro